System for lowering a subsea device from a vessel

ABSTRACT

A system for lowering a subsea device from a vessel floating on a body of water. Means are provided to prevent the subsea device from striking the vessel as it goes through the sea-air interface. In a preferred embodiment, an access well means such as a tube extends downwardly through the vessel to below the wave action of the body of water. The outer wall of the subsea device is provided with roller members urged against the inner wall of the access well. Other means of moving a subsea device through the sea-air interface are also disclosed.

United States Howard F? atent [54] SYSTEM FOR LOWERING A SUBSEA DEVICE FROM A VESSEL George C. Howard, Tulsa, Okla.

Pan American Petroleum Corporation, Tulsa, Okla.

May 25, 1970 Inventor:

[73] Assignee:

Filed:

Appl. No.:

Related US. Application Data Continuation of Ser. No. 861,221, Sept. 15, 1969, abandoned, which is a continuation of Ser. No. 737,556, June 17, 1968, abandoned.

[56] References Cited UNITED STATES PATENTS 1,623,148 4/1927 Wilson .....61/69A 1 Feb. 15,1972

1,997,149 4/1935 Lake ..6l/69 R 3,340,928 9/1967 Brown...

2,988,144 6/ 1961 Conrad 3,259,198 7/1966 Montgomery et al 175/7 Primary Examiner-Trygve M. Blix Attorney-Paul F. Hawley and John D. Gassett [57 1 ABSTRACT 14 Claims, 9 Drawing Figures PAIENTEBFEB 15 I972 SHEET 1 [IF 4 INVENTOR. GEORGE C. HOWARD ATTORNE Y- PATENTEHFEH 15 m2 3.641.961

SHEEI 2 [IF 4 INVENTOR. GEORGE C. HOWARD ATTORNEY PATENTEBFEB 15 B72 3,641,961

SHEET 3 0F 4 INVENTOR. GEORGE C HOWARD ATTORNEY PATENTEBFEBIS I972 3.541.961

sum a 0r 4 FIG.4

INVENTOR.

GEORGE C. HOWARD A T TORNE Y SYSTEM FOR LOWERING A SUBSEA DEVICE FROM A VESSEL This is a continuation of application Ser. No. 861,221, now abandoned, filed Sept. 15, 1969; which in turn was a continuation of application Ser. No. 737,556 now abandoned, filed June 17, 1968.

This invention relates to the lowering of a subsea device from a vessel floating on a body of water. It relates especially to means whereby the effect of the wave and ship motion on the device is minimized.

BACKGROUND OF THE INVENTION One of the major problems involved in conducting diving operations at sea is that associated with transferring the transport capsule through the sea-air interface. This problem is accentuated in rough seas. Ordinarily, in lowering subsea devices such as a diving capsule, the diving capsule is attached to a cable and picked up by a crane. The crane then swings the capsule over the side of the vessel and then lowers the capsule into the water. In relatively calm water no great problem is presented. However, as the sea gets rougher, the problems become greater. The problems which are encountered include the hard-to-control movement of the capsule. For example, if the sea has a strong current, the capsule may be blown laterally. If the sea has high waves, then the wave motion on the capsule is invariably different from that of the ship. Thus the crane which is supported by the ship has one movement and the capsule another. Just the change in velocity can cause serious damage to whatever may be in the diving capsule. If the diving capsule is occupied by men, then such change in motion is very uncomfortable to the men and, in some cases, may even cause bodily injury. In some cases the diving capsule may even be bashed against the side of the vessel. It is the recognition of these problems which prompted the invention disclosed herein.

BRIEF DESCRIPTION OF THE INVENTION This invention concerns an apparatus for lowering a subsea device through the sea-air interface from a vessel floating on a body of water. In a preferred embodiment, a vertical opening is provided through the ship and at the lower end of this opening a long tubular member extends into the water. The lower end of the tube extends to well below the wave action commonly associated with the surface and near-surface of the sea. The pipe, for example, can extend down 50 feet. A diving capsule or other subsea device is lowered through this access well which includes the downwardly extending tubular member. The outer wall of the diving capsule is provided with guide means for contacting the inner wall of the access well. The guide means preferably takes the form of roller means for rolling along the inner wall of the access well means. These rollers are urged outwardly against the wall and preferably are provided with (l) braking and (2) means for controlling the direction of rotation of the rollers.

In operation, the diving bell is lowered through the diving access well means. When it passes through the air-sea interface it is within the tube and is guided thereby so that any lateral movement which the diving capsule encounters is the same lateral movement as that of the ship. Thus, the diving capsule is not bashed against the ship. By the time the diving capsule is free of the access well, it is well below the ship and is ordinarily in relatively calm water.

Various objects and a better understanding of the invention can be had from the following description taken in conjunction with the drawings.

DRAWINGS FIG. 1 illustrates a vessel floating on a body of water and having an access well means extending downwardly therefrom;

FIG. 2 illustrates another means of lowering a diving capsule through the sea-air interface utilizing lines which are anchored to the ocean floor;

FIG. 3 illustrates the use of the system of FIG. 2 in conjunction with lowering the diving capsule through the access well of the device as shown in FIG. 1;

FIG. 4 illustrates an enlarged view of a portion of the vertical well and the transfer capsule of FIG. 1;

FIG. 5 illustrates another modification of the transfer capsule in the access well;

FIG. 6 is a section taken along the line of 6-6 of FIG. 5;

FIG. 7 is a section taken along the line 77 of FIG. 5;

FIG. 8 is a section taken along the line 8-8 of FIG. 5;

FIG. 9 is a top view of only the transfer capsule of FIG. 5.

DETAILED DESCRIPTION Attention is first directed to FIG. 1. Shown thereon is a vessel l0 floating on a body of water 12 having a bottom 14 and a surface 16. Vessel 10 is provided with a vertical opening or well 18. Mounted in this opening and extending downwardly is a tube 20. The lower end of this tube is flared outwardly into a funnel-shaped portion 22. The funnel portion 22 is used as a guide means for guiding the device back into the funnel. Well 18 is enlarged at the bottom to provide room, e. g., flared section 19, to receive funnel portion 22. The lower end of the tube 20 extends to below the wave action normally associated with the surface or near-surface water. For example, this can be 40 to 50 feet below the surface of the body of water.

Tube 20, when in the position indicated in FIG. 1, adds considerable stability to vessel 10. This is helpful when being used for the purpose intended. However, when the vessel is moving from one location to another, tube 20 imparts considerable drag on the vessel and is therefore a detriment. Therefore, means are provided such as by crane 34 for lifting tube 20 up through opening 18. This means for lifting this can simply be a crane which attaches to shoulder members 24. Shoulder members 24 merely rest on a reinforced portion of the deck 26 of vessel 10 and supports pipe 20. Alternatively, gear racks 82 as shown in FIG. 4 can be provided on the outer wall of tube 20 and jacked up or down by mating gear means (not shown) on ship 10.

Pipe 20 fits snugly into well 18. Guide funnel 22 can be attached to pipe portion 20 by conventional means such as bolts 28 and if the vessel is to be moved a very great distance, divers remove bolts 28 and funnel 22 is lifted to the deck and pipe portion 20 can be laid on the deck of vessel 10. However, it is contemplated that in moving from one location to another, funnel 22 will rest in enlarged well portion 19 and pipe 20 will extend above the deck of vessel 10.

Attention is next directed to diving capsule 30 which is shown in an enlarged view in FIG. 4. Diving capsule 30 can be any subsea device which is desired to be lowered into the water. This device is supported by a cable 32 which goes to a crane 34. Diving capsule 30 is provided with guide means which may be static but are preferably rollers 36 which are urged outwardly by resilient means 38. Resilient means 38 can be springs, or if the device is rather large it can be hydraulic pistons. Rollers 36 are provided with brakes 40 and gear means 42 for selectively controlling the direction of rotation of the rollers.

Capsule 30 may be provided with an inflatable tube 84. If the capsule should break loose from the ship, e.g., cable 32 break or have to be severed, then tube 84 is inflated from a gas source within capsule 30. The capsule then rises to the surface of the water. The tube 84 may also be inflated within tube 20 to cause capsule 30 to resist movement therein as it is pulled therethrough.

Attention is directed to FIG. 5 to illustrate a more positive roller means for the transfer capsule. Shown therein is tube 20 having vertical racks 44 along the inside wall thereof. Capsule 30A is provided with roller gears 36A which, as shown in FIG. 4, are used instead of rollers 36. These gears 36A are urged outwardly similarly as the rollers 36 and engage gears 30. Means are provided so that these gears can rotate in only a selected direction which can be changed from within the capsule. This is a common mechanical feat and details of such means are not shown.

It is important that the gears 36A of the diving capsule mate with rack 44. Guide means are provided to insure this. A guide groove 50A which is wide at the bottom as shown in FIG. 8 and progressively narrows down as shown at 50B and 50C in FIGS. 6 and 7 is provided. As shown in FIG. 9, there are guide rods 80 which are provided on the outer wall of capsule 30. These guide rods are biased outwardly and upon a force being applied on the outer end thereof are retracted or forced inwardly. These guide rods 80 are useful for guiding gears 36A into engagement with gear rack 44.

In operation and referring especially to FIG. 1, capsule 30 is connected to line 32 and the passengers board the capsule in an ordinary manner. Capsule 30 is lowered down through the access well 20. As it reaches water surface 16, the sea-air interface will have an effect on capsule 30. However, as this interface is within well 20, the vertical effect will be essentially the same as that on the ship, provided capsule 30 is fairly heavy. Currents of the surface of the water will not have any different level effect on capsule 30 than they do on the ship because the capsule 30 is confined within the well 20 which is secured to the ship. Thus the capsule 30 cannot be bashed into the vessel. AS the capsule is lowered the rollers are set such that the capsule can only move downwardly and thus cannot be surged upwardly in the well. When the capsule reaches the end of pipe 20 it is ordinarily in relatively calm water. The capsule 30 then is lowered to whatever depth is desired. I have used the term diving capsule; however, this can be any subsea device. For example, it can be a self-propelled submarine so that it could explore various areas beneath the ship. When it is desired to raise the capsule, crane 34 raises cable 32 and the capsule 30 is guided in through funnel 22 and through pipe 20. This time when it goes up, rollers 36 can only move in the direction permitting the capsule to go up. Thus the capsule cannot oscillate in the vertical direction within the pipe 20. This is an especially important feature as it goes through seaair interface at the surface. Pipe 20 is preferably provided with perforations 21 as shown in FIG. 1. This lets the water readily escape when the device 30 is raised, which raising has a pistonlike effect.

When the diving bell or capsule 30A ofFIG. is pulled upwardly from below the funnel 22A into well 20, the guide rods 80 encounter that portion of funnel 22A of FIG. 8 identified as 50A. As the capsule is pulled upwardly, guide rods 80 are within that portion specified as 50B in FIG. 7. By the time guide rods 80 reach level indicated at 85 of FIG. 5, the guide rods are in a very small confined portion shown as 50C in FIG. 6. This assures that gears 36A mate with gear rack 44. The device is then pulled upwardly and gears 36A are adjusted to rotate to permit only upward movement of capsule 30. This prevents oscillation within well 20.

Attention is now directed especially to FIG. 2 which shows another device for a system for lowering a subsea device through the sea-air interface. Shown thereon is an anchor means 50 which is secured in the bottom of the ocean floor 52. Supported on the body of water 12 is a vessel 54. A crane 56 supports pulleys 58 and 60 over the side of vessel 54. A diving capsule or other device 62 is supported in the water by two cables. A first cable 64 is attached to the upper end of capsule 62. Cable 64 passes over pulley 58 and goes to winch means 72. A second cable 68 is attached to the lower end of capsule 62 and extends downwardly around pulley 70 which is attached to anchor 50. Preferably, pulley 70 is connected to anchor 50 by explosive bolt means 71 which can be detonated by sonic pulses. Cable 68 then loops back upwardly through the interior vertical passage through the capsule 62 upwardly over the pulley 60 and to a winch means 72 supported on crane 56. Winch means 72 is connected to a constant tensioning device 66 so that the tension on the cables 64 and 68 remains relatively constant. Means are provided at 67 for severing cable 68 below capsule 62.

Cables 64 and 68 are connected to winch means 72 in such a manner that when the winch drum rotates, one of the cables is payed out and the other is taken in. The operation of the device of FIG. 2 is rather straight forward. First, an anchor means 50 is set with pulley 70 and cable 68 running through the pulley 70. This anchor means can be those which are commercially available and which are explosively set such as those manufactured by Aerojet General Corporation and designated as an embedment anchor. Alternatively, anchor 50 can be a large block of cement or other mass set on the ocean floor. The capsule is then secured to lines 68 and 64 while still on the deck of vessel 54. Then the divers enter vessel 62. Crane 56 then picks up the system such as by lifting on pulleys 58 and 60 and swings the capsule over the side of the vessel. Then constant tensioning means 66 places the desired tensioning on cables 64 and 68. Then winch means 72 by taking up on line 68 pulls the capsule 62 down through the water. As the lines are anchored to the ocean floor there is a steady downward pull on capsule 62. Recovery operations of the capsule 62 are just the reverse of the lowering operations, i.e., the capsule is pulled upward by means of line 64 at a constant rate.

Occasionally in using the device of FIG. 2, one gets adverse lateral movement of capsule 62, especially if the currents are extremely strong. The effects of this lateral movement can be reduced by combining the device of FIG. 2 with FIG. 1. This modification is shown in FIG. 3. There, anchor 50 is anchored in the ocean floor directly beneath vertical pipe 20. Capsule 62 is then lowered into the water, not over the side but rather down through vertical pipe 20. Capsule 62 closely fits the walls of tube 20 and thus its lateral movement is limited to that of the vessel and tube 20. Otherwise the operation is similar to that ofFIG. 2.

Although the invention has been described with a great deal of detail, it is possible to provide still other embodiments without departing from the spirit or scope of the invention.

I claim:

1. An apparatus for use with a vessel floating on a body of water which comprises:

a cargo-carrying device;

an access well means including a vertical hollow member extending downwardly beneath said vessel to a depth below the wave action of said body of water, said vertical hollow member of said access well means at all times being free of contact with the bottom of said body of water;

means to move said cargo-carrying device through said well means.

2. An apparatus as defined in claim 1 including guide means on the outer wall of said device for contacting the inner wall of said hollow member of said access well means.

3. An apparatus as defined in claim 2 in which said guide means includes rollers for rolling along the inner wall of said hollow member of said access well means, means urging said rollers against the inner wall of said hollow member of said access well means, means for limiting the direction of rotation of said rollers, and brake means for said rollers.

4. An apparatus as defined in claim 1 in which the wall of said hollow member of said access well means has perforations therein.

5. An apparatus as defined in claim 4 in which said cargocarrying device is a diving bell.

6. An apparatus as defined in claim 1 including:

an anchor at the bottom of said body of water;

a pulley connected to said anchor;

a constant tensioning means supported by said vessel;

a first line connected to said subsea device and extending to said constant tensioning means;

a second line connected to the lower end of said cargo-carrying device and extending downwardly through said pulley and back up through said hollow member of said access well means to said constant tensioning means.

7. An apparatus as defined in claim 1 in which said means to move said device includes a line, a power source, and means for applying constant tension on said line.

8. An apparatus as defined in claim 1 including a vertical gear rack on the interior wall of said access well means;

gear wheels;

means supporting said gear wheels from said cargo-carrying device and urging said gear wheels outwardly to engagement with said gear rack; and

means controlling the direction of rotation of said gear wheels.

9. An apparatus as defined in claim 8 including a funnel means at the lower end of access well means, said funnel having guide means on the interior, said guide means encompassing nearly the entire circumference of said funnel means at its lower end, said guide means being progressively restricted toward the upper end of said funnel means;

retractable, outwardly biased guide rods on the outer wall of said cargo-carrying device for engaging said guide means.

10. An apparatus as defined in claim 1 including an inflatable tube surrounding said cargo-carrying device.

11. An apparatus as defined in claim 7 including means to sever said second line below said diving capsule.

12. An apparatus for lowering a diving capsule from a vessel floating on a body of water which comprises:

a tubular member extending downwardly and supported from said vessel, the lower end of said tubular member being below the wave action of said body of water;

an anchor means in the bottom of said body of water;

a pulley means on said anchor means;

winch means;

a first line extending from said diving capsule to said winch means;

a second line extending from the lower side of said diving capsule downwardly through said pulley and back upwardly through said winch means on said vessel;

said first line and said second line extending through said tubular member for transferring said diving capsule therethrough.

13. An apparatus as defined in claim 12 including constant tensioning means positioned between, and connecting, said winch means and said vessel.

14. A method of lowering a subsea cargo-carrying device from a vessel floating on a body of water which comprises:

supporting from said vessel a vertical hollow member extending downward to a depth below the wave action of said body of water; maintaining the lower end of said vertical hollow member at a position above the bottom of said body of water; lowering said cargo-carrying device through said vertical hollow member and out the lower end thereof; manipulating said device through the water laterally from said vertical hollow member.

* i ii 1.: 

1. An apparatus for use with a vessel floating on a body of water which comprises: a cargo-carrying device; an access well means including a vertical hollow member extending downwardly beneath said vessel to a depth below the wave action of said body of water, said vertical hollow member of said access well means at aLl times being free of contact with the bottom of said body of water; means to move said cargo-carrying device through said well means.
 2. An apparatus as defined in claim 1 including guide means on the outer wall of said device for contacting the inner wall of said hollow member of said access well means.
 3. An apparatus as defined in claim 2 in which said guide means includes rollers for rolling along the inner wall of said hollow member of said access well means, means urging said rollers against the inner wall of said hollow member of said access well means, means for limiting the direction of rotation of said rollers, and brake means for said rollers.
 4. An apparatus as defined in claim 1 in which the wall of said hollow member of said access well means has perforations therein.
 5. An apparatus as defined in claim 4 in which said cargo-carrying device is a diving bell.
 6. An apparatus as defined in claim 1 including: an anchor at the bottom of said body of water; a pulley connected to said anchor; a constant tensioning means supported by said vessel; a first line connected to said subsea device and extending to said constant tensioning means; a second line connected to the lower end of said cargo-carrying device and extending downwardly through said pulley and back up through said hollow member of said access well means to said constant tensioning means.
 7. An apparatus as defined in claim 1 in which said means to move said device includes a line, a power source, and means for applying constant tension on said line.
 8. An apparatus as defined in claim 1 including a vertical gear rack on the interior wall of said access well means; gear wheels; means supporting said gear wheels from said cargo-carrying device and urging said gear wheels outwardly to engagement with said gear rack; and means controlling the direction of rotation of said gear wheels.
 9. An apparatus as defined in claim 8 including a funnel means at the lower end of access well means, said funnel having guide means on the interior, said guide means encompassing nearly the entire circumference of said funnel means at its lower end, said guide means being progressively restricted toward the upper end of said funnel means; retractable, outwardly biased guide rods on the outer wall of said cargo-carrying device for engaging said guide means.
 10. An apparatus as defined in claim 1 including an inflatable tube surrounding said cargo-carrying device.
 11. An apparatus as defined in claim 7 including means to sever said second line below said diving capsule.
 12. An apparatus for lowering a diving capsule from a vessel floating on a body of water which comprises: a tubular member extending downwardly and supported from said vessel, the lower end of said tubular member being below the wave action of said body of water; an anchor means in the bottom of said body of water; a pulley means on said anchor means; winch means; a first line extending from said diving capsule to said winch means; a second line extending from the lower side of said diving capsule downwardly through said pulley and back upwardly through said winch means on said vessel; said first line and said second line extending through said tubular member for transferring said diving capsule therethrough.
 13. An apparatus as defined in claim 12 including constant tensioning means positioned between, and connecting, said winch means and said vessel.
 14. A method of lowering a subsea cargo-carrying device from a vessel floating on a body of water which comprises: supporting from said vessel a vertical hollow member extending downward to a depth below the wave action of said body of water; maintaining the lower end of said vertical hollow member at a position above the bottom of said body of water; lowering said cargo-carrying device through said vertical hollow member and out the lower end thereof; manipulating said device thRough the water laterally from said vertical hollow member. 